1. Field of the Invention
The present invention relates to a film with excellent gas barrier properties and an organic device using the same, particularly a laminated gas barrier film which is suitable for substrates or covering films of various organic devices. Furthermore, the invention relates to an organic device with excellent durability and flexibility using the foregoing gas barrier film, particularly an organic EL device.
2. Description of the Related Art
In recent years, in organic devices such as liquid crystal display devices, solar cells and electroluminescent (EL) devices, the use of a transparent plastic film which is thin, light and excellent in flexibility in place of a glass substrate which is heavy and easy to break is being studied. In view of the matters that transparent plastic substrates are easy to realize a large area and able to be applied for a roll-to-roll production system, they are good in productivity as compared with glasses and advantageous on the point of a cost reduction.
However, the transparent plastic substrates involve a problem that they are inferior in gas barrier properties to glasses. In organic devices, in general, constitutional materials are easy to cause deterioration or change of properties by water or air. For example, when a base material with inferior gas barrier properties is used for a substrate of liquid crystal display device, it deteriorates a liquid crystal in a liquid crystal cell, and a deterioration site becomes a display defect, thereby reducing the display grade.
In order to solve these problems, a gas barrier function may be imparted to the foregoing plastic film substrate per se, or the whole of the device may be sealed by a transparent plastic film with gas barrier properties. As a gas barrier film, films having a metal oxide thin film formed on a plastic film are generally known. As a gas barrier film to be used for liquid crystal display devices, for example, there are films having silicon oxide vapor deposited on a plastic film (see, for example, JP-B-53-12953 (pages 1 to 3)) and films having aluminum oxide vapor deposited on a plastic film (see, for example, JP-A-58-217344 (pages 1 to 4)). All of these films have water vapor barrier properties to an extent that their water vapor permeability is about 1 g/m2/day. However, in recent years, the development of organic EL displays or high-definition color liquid crystal displays which are required to have higher barrier properties is being advanced, and base materials capable of being used therefor and keeping transparency and having high barrier properties and in particular, those having water vapor barrier properties and having performance such that a water vapor permeability thereof is less than 0.1 g/m2/day are being required.
In order to respond to these requirements, as a measure capable of being expected to have higher barrier performance, the fabrication by a sputtering method or CVD method for forming a thin film using plasma emitted by glow discharge under a low-pressure condition is studied. Also, there is proposed a technology for preparing a barrier film having an organic layer/inorganic layer alternate laminated structure by a vacuum vapor deposition method (see, for example, U.S. Pat. No. 6,413,645B1 (page 4, [2-54] to page 8, [8-22])).
In fabricating both an organic layer and an inorganic layer, in order to obtain high barrier properties, it is important that foreign matters such as dusts are not mixed as far as possible. Technical disclosures regarding barrier films having an antistatic layer have been made until now. However, these were aimed to give an antistatic layer after forming a barrier layer, thereby preventing handling or dust attachment on a finished film (see, for example, JP-A-2005-305801 (pages 1 to 11)). Also, there are an example of a gas barrier film in which a barrier layer is formed using an antistatic film having a conductive fine particle mixed therein (see, for example, JP-A-2002-137323 (pages 1 to 7)); and an example of a barrier film in which a coating material having a conductive fine particle mixed therein is coated on a substrate film, and a barrier layer is provided on the opposite side to the coated surface (see, for example, JP-A-8-294991 (pages 1 to 12) and JP-A-2006-88538 (pages 1 to 38)). However, in the former, when the fine particle is mixed in the substrate film, the smoothness of the film surface becomes worse, and as a result, the barrier properties are not so high. Also, in the latter, there is pointed out a problem that the formation of the barrier layer is limited to one surface, and the mixed conductive fine particle peels off, thereby affecting the fabrication of the barrier layer. On the other hand, though a method of using an acrylic ester having a quaternary ammonium salt is also disclosed, the antistatic properties in vacuum are deteriorated, whereby the resultant is no longer useful (see, for example, JP-A-10-58621 (pages 1 to 8)). Also, though a method of using an ITO thin film in which an antistatic layer is formed by a sputtering method or polyaniline or the like is disclosed, this method is not so preferable from the standpoint of costs (see, for example, JP-A-2001-246688 (pages 1 to 6) and JP-A-11-28780 (pages 1 to 9)). The formation of an antistatic layer capable of solving these various problems and being used for the fabrication of a barrier film has been desired.